A thug forced his way into a house and assaulted the homeowners in what is believed to be a targeted attack.
The assault on a man and woman, who are both in their 40s, in Croydon Road, Caterham, left the man with facial fractures.
He was taken to East Surrey Hospital, Redhill, for treatment.
The attack happened at about 9.45pm Friday, January 16.
Investigating officer Detective Constable Colin Snell said: "Although we are still in the early stages of this investigation I would like to reassure the public that we do not believe this was a random assault.
"We are making a number of enquiries to establish the full circumstances surrounding the incident."
Police have arrested a 37-year-old man in connection with the investigation.
He has been bailed until February 20.
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